骨髓间充质干细胞在医学领域中的研究与应用

目的:骨髓间充质干细胞主要存在于全身结缔组织和器官间质中,自我更新和增殖能力强,在适宜的微环境里具有多向分化潜能。文章就骨髓间充质干细胞的生物学特性及其在医学领域应用的最新进展做一综述。资料来源:应用计算机检索PUBMED2000-01/2006-12期间的相关文章,检索词为“mesenchymal stem cell”,并限定文章语言种类为English。同时计算机检索中国期刊全文数据库2000-01/2006-12期间的相关文章,检索词为“骨髓间充质干细胞”,并限定文章语言种类为中文。资料选择:对资料进行初审,并查看每篇文献后的引文。纳入标准:文章所述内容应与骨髓间充质干细胞的发展现状及其临床应用相关。排除标准:重复研究或较陈旧的文献。资料提炼:共收集到160篇相关文献,68文献符合纳入标准,排除的92篇文献为内容陈旧或重复。选取符合纳入标准的30篇文献进行分析,分别涉及骨髓间充质干细胞的分离培养和鉴定、在医学领域中的应用、当前存在的问题及展望。资料综合:骨髓间充质干细胞是一类具有分裂增殖和多向分化潜能的干细胞,在适宜的诱导条件下可定向分化为成骨细胞、成软骨细胞、脂肪细胞、腱细胞、肌肉细胞和神经细胞等,且已在退行性及缺损性疾病、心血管疾病、肝移植、肺纤维化等疾病治疗方面取得良好效果。目前骨髓间充质干细胞在体内的细胞生物学和分子生物学作用机制仍不清楚,如何限定体内外诱导条件使其向所需细胞或组织定向分化以及移植时机、是否具有致瘤性等问题尚需深入研究。结论:骨髓间充质干细胞具有易获得、易培养、低免疫原性、易于外源基因的转入和表达等特性,已成为具有细胞治疗和基因治疗临床疾病潜在实用价值的有效载体。     

Analysis of antibodies against components of the autonomic nervous system in diabetes mellitus

Antibodies to autonomic nervous system structures have previously been detected using a complement fixation immunofluorescence test in the sera of patients with insulin-dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM). These antibodies might play a role in the aetiology of autonomic neuropathy. Sera from 45 IDDM, 40 NIDDM and 52 control subjects were tested by immunofluorescence for antibodies to human sympathetic ganglia, human adrenal medulla and rabbit vagus nerve. The use of human sympathetic ganglia was compared with rabbit tissue for the detection of sympathetic ganglia antibodies; the results for these autonomic nervous system antibodies were also compared with results using an ELISA. There was no relationship between the presence of antibodies detected by ELISA and those detected by immunofluorescence, but of 14 IDDM patients with thyroid antibodies, 12 had autonomic nervous system antibodies detected by either immunofluorescence or ELISA (p < 0.005 compared to patients without thyroid antibodies). To further characterize the autoantigen(s), immunoblotting was performed. An adrenal antigen corresponding to 74 kDa was detected in sera from three patients, only one of whom had antibodies detectable by ELISA and immunofluorescence. One IDDM serum showed specific binding to a vagus nerve antigen corresponding to 33 kDa. No specific binding to sympathetic ganglia antigen was demonstrated. Antibodies against autonomic nervous system antigens are an inconsistent feature of diabetes, and appear more associated with coincidental autoimmunity against other organs such as the thyroid.      

Metabolic Studies in Kidney Stone Disease

Patients with kidney stones (n=59) and healthy controls (n=31)collected a 24-hour urine sample and later underwent a 6-hour‘fast and load’ test in which an oral calcium loadwas taken after 2 hours. In the 24-hour urine sample, mean calciumexcretion was higher in patients than controls, while mean urate,oxalate and citrate levels were similar. The patients had higherlevels of fasting plasma calcium, serum calcitriol and fastingurinary calcium, and lower levels of plasma phosphate than didthe controls. Following the calcium load, plasma and urinarycalcium increased similarly in both groups. Serum parathyroidhormone (PTH) levels were similar in both groups and decreasedsimilarly following the calcium load. Multiple linear regression, relating the presence or absenceof stone formation to all variable, found the only variablessignificantly related to stone formation to be plasma levelsof calcium (p<0.001) and phosphate (p=0.001) and fastingurinary area (p<0.001), and 24-hour urinary calcium excretion(p<0.05). Urinary oxalate and citrate were not related tostone formation. The data do not support the hypothesis thatprimary stimulation by calcitriol produces a normal fastingplasma calcium level, with an exaggerated increase after anoral calcium load. The findings instead suggest an abnormalityof parathyroid cell ‘set point’, such that PTH secretioncontinues until the plasma calcium level is a little higherand the phosphate a little lower than in controls.     

Is high-resolution ultrasonography suitable for the detection of temporomandibular joint involvement in children with juvenile idiopathic arthritis?

Objectives:

The purpose of this study was to determine the potential of high-resolution ultrasonography for the detection of temporomandibular joint (TMJ) changes in children with juvenile idiopathic arthritis (JIA).

Methods:

We investigated prospectively 20 children (17 female and 3 male; mean age 11.06 years, standard deviation 3.43 years) with TMJ disorders caused by JIA, over a period of 16 months. Using a 12 MHz array transducer, four images in each TMJ (160 images) were acquired. Each image was analysed with regard to five different aspects (condylar erosion, thickness of the condylar disc, synovial thickness, joint effusion and enlargement of the intra-articular space).

Results:

Diagnosis of JIA was ensured for every child and involvement of the TMJ was proven by MRI. Overall 287 changes (35.9%) were detected by using high-resolution ultrasonography. On 124 images (77.5%) condylar erosions were diagnosed; on 55 images (34.4%) synovial thickness was abnormal; on 48 images (30%) we could see higher thickness of the condylar disc; on 40 images (25%) irregularities of the bony surface were detected; and on 20 images (12.5%) we found joint effusion.

Conclusion:

High-resolution ultrasonography could be a sufficient diagnostic method, especially for the detection of condylar involvement in children with JIA, even if not all parts of the TMJ are visible for ultrasonography. High-resolution ultrasonography is a valuable tool in particular situations: (i) when MRI examination is not available; (ii) when children fear MRI examination; (iii) in more advanced stages of JIA; and (iv) for monitoring the progression of TMJ involvement and response of therapy.     

Heterosexually acquired human immunodeficiency virus infection and the United States blood supply: considerations for screening of potential blood donors. HIV Blood Donor Study Group

The impact of heterosexual transmission of the human immunodeficiency virus (HIV) on the United States blood supply was assessed, and deferral criteria that may exclude potential donors who are at high risk for heterosexually acquired HIV infection were evaluated. Interviews were conducted with 508 HIV-seropositive blood donors from May 1, 1988, to August 31, 1989 (Phase 1), and with 472 donors from January 1, 1990, to May 31, 1991 (Phase 2), at 20 blood centers. From Phase 1 to Phase 2, the overall HIV prevalence decreased from 0.021 to 0.018 percent (p < 0.001). HIV risk factors among HIV-1-seropositive donors were similar during both study phases. Eleven percent of the men and 56 percent of the women reported as their only risk that they had a heterosexual partner who was at increased risk for HIV or was known to have HIV. These percentages were similar during both study periods. During Phase 2, 13 percent of the men and 17 percent of the women with heterosexual transmission risk had a positive serologic test for syphilis, hepatitis B core antibody, or hepatitis C antibody. Among HIV- 1-seropositive donors reporting heterosexual risk, the median numbers of previous-year and lifetime sex partners for men were 2 and 30, respectively; for women, those numbers were 1 and 7, respectively. Thirty-one percent of the men and 6 percent of the women reporting heterosexual transmission risk also reported having had syphilis or gonorrhea within 3 years of donation. It is concluded that the impact of heterosexual transmission of HIV infection on transfusion safety is not worsening at this time.(ABSTRACT TRUNCATED AT 250 WORDS)     

载溶菌酶聚乳酸-聚羟基乙酸共聚物微球的形成机制

目的：分析载溶菌酶聚乳酸-聚羟基乙酸共聚物微球的形成机制. 方法：实验于2005-03/07在暨南大学生物材料研究室完成.采用双乳液法（W/O/W法）制备聚乳酸-聚羟基乙酸共聚物微球.通过改变微球的制备条件[初乳时间（15,30,45,60,120 s）、初乳速度（6 000,10 000,14 000,18 000,22 000 r/min）、聚乙烯醇质量浓度（0,5,25,50,100 g/L）、复乳时间（0.5,2.5,5,8,11.5 h）、复乳速度（200,400,600,800,1 000 r/min）、初始药物质量浓度（0,20,40,60,80,100 g/L）、内/外水相添加剂（吐温-80、葡聚糖、蔗糖、氯化钠）、油相潜溶剂（丙酮、甲醇、乙醇、二甲基亚砜）],制备不同表面结构和内部结构的聚乳酸-聚羟基乙酸共聚物微球,扫描电镜下观察微球内/外部结构. 结果：制备出不同表面结构和内部结构的聚乳酸-聚羟基乙酸共聚物微球.微球表面主要呈3种状态：光滑致密、光滑多孔或粗糙多孔.微球的内部呈多孔洞或核壳结构.①初乳速度较低时（＜10 000 r/min）,微球表面以光滑为主,内部多孔,中间有一大的核心;初乳速度较高时（＞ 18 000 r/min）,微球表面较为粗糙,内部孔洞致密,呈蜂巢状.②不同初乳时间制备的微球仍以表面平滑为主,有的微球表面有孔洞,大小在几个微米左右,微球内部仍然是蜂巢状结构.③聚乙烯醇质量浓度影响复乳的稳定性,从而对微球的形成过程影响很大.④复乳时间对微球形成过程的影响较为明显,反应时间过短（＜0.5 h）,微球未充分固化,增加反应时间,球形度相对提高.⑤复乳速度直接影响到复乳体系的稳定.速度较低时（200 r/min）,形成的微粒体积较大,易形成不规整的大块聚集体.随着搅拌速度的增加,微粒球形度也相应提高.但是当速度过大时（1 000 r/min）,微粒容易破裂形成碎散的不规则聚集体.⑥初始药物质量浓度对微球形成过程的影响很大,药物质量浓度高时（100 g/L）,微球表面粗糙,碎片较多;药物质量浓度为60 g/L时,微球表面光滑,球形度很好.⑦不同的内水相添加剂（吐温-80、葡聚糖、蔗糖、氯化钠）制备的微球球形度均较好,微球表面平滑,但是存在部分微球相互粘连的情况.外水相添加蔗糖和氯化钠,微球的球形度较好,微球之间无粘连.但外水相添加吐温-80,形成的产物体积较大且形成许多不规则的聚集体.外水相添加葡聚糖形成的微球表面粗糙且含较多碎屑.⑧选用不同的油相潜溶剂（丙酮、甲醇、乙醇、二甲基亚砜）均存在部分的微球融合现象. 结论：从多角度系统阐述了载溶菌酶聚乳酸-聚羟基乙酸共聚物微球的形成机制.不同的制备条件对微球的结构影响各异,微球的尺寸分布及形态性能是初乳与复乳过程中各种影响因素综合作用的结果.     

小百部的甾体皂甙成分

从云南产小百部(Asparagus filicinus Buch.-Ham)的根中分离到四个甾体皂甙,经光谱分析和化学降解,确定了结构,其中三个为新化合物,分别命名为小百部甙A(Ⅰ),小百部甙B(Ⅱ)和小百部甙C(Ⅲ)。另一个为已知皂甙Asp-Ⅳ的22-甲氧基化物(Ⅳ)。此外还分离到β-蜕皮甾酮(β-ecdysone,Ⅴ)。     

Expression of CYP1B1 but not CYP1A1 by primary cultured human mammary stromal fibroblasts constitutively and in response to dioxin exposure: role of the Ah receptor

The expression of CYP1B1 in human mammary fibroblasts (HMFs) was characterized as a potential modulator of their individual function as well as effects on adjacent mammary epithelia. We have used these characteristics to explore the diversity of fibroblast cells isolated from reduction mammoplasty patients and from different breast locations in breast cancer patients (tumors, peripheral to tumor and skin). These parameters have also been used to examine differences between two donors. The results have shown that while none of these HMFs expressed a detectable CYP1A1 protein basally or in response to TCDD, they all expressed CYP1B1 constitutively at similar levels (0.5-0.9 pmol/mg microsomal proteins) and they were induced by TCDD (up to 5-fold) consistent with mediation by the Ah receptor (AhR). DMBA metabolism by HMFs exhibited high proportions of 5,6-, 10,11- and 3,4-dihydrodiols, a profile that is typical of human CYP1B1 regioselectivity. RT-PCR followed by Southern blot analyses demonstrated that CYP1B1 mRNA expression in HMFs parallels levels of respective microsomal proteins. The AhR is expressed in these HMFs as two cytosolic forms (approximately 106 and 104 kDa) and a substantial proportion of the 104 kDa form was localized to the nucleus even prior to TCDD treatment. In all HMFs isolated directly from collagenase digested breast tissues the AhR is expressed at levels 10-fold lower than in breast epithelial cells. However, HMFs that were isolated after serial passaging of mammary epithelial cultures had shown much higher levels of the AhR expression and more dramatic TCDD-induced down-regulation (>80% in 24 h) associated with more efficient nuclear translocation. These differences suggested the presence of two functionally distinct subtypes of HMFs: interstitial stromal fibroblasts that are readily released by collagenase digestion of breast tissues, and lobular stromal fibroblasts which are more tightly associated with the breast epithelia.      

Abnormal assembly of membrane proteins in erythroid progenitors of patients with beta-thalassemia major

The life threatening anemia in beta-thalassemia major (Cooley's anemia) is characterized by profound intramedullary lysis, the cause of which is incompletely understood. Using marrow obtained from beta thalassemia major patients undergoing allogeneic bone marrow transplantation in Pesaro Italy, it became possible to directly study the mechanism of the intramedullary hemolysis. Based on our previous studies, we hypothesized that the unmatched alpha globin chains would interfere with normal assembly of erythroid precursor membrane proteins. Patient and control erythroid precursors were reacted with monospecific polyclonal rabbit antibodies directed against spectrin, band 3, and band 4.1 and with a monoclonal anti-alpha globin chain antibody. Using laser confocal fluorescence microscopy, normal erythroid precursors show no alpha globin chain accumulation and exhibited uniformly smooth rim fluorescence of the three membrane proteins. In some thalassemic precursors, spectrin appeared to interact with large alpha globin accumulations, and in many of these cells the spectin appeared clumped and discontinuous. Band 4.1 interacted strongly with accumulations of alpha globin in thalassemic precursors to produce bizarrely clumped zones of abnormal band 4.1 distribution. Band 3 was incorporated smoothly into thalassemic erythroblast membranes. However, the proerythroblasts and basophilic erythroblasts were significantly deficient in band 3. Thus, accumulations of alpha globin in beta- thalassemia major colocalized with and disrupt band 4.1 and spectrin assembly into the membrane. The cause of deficient band 3 incorporation into thalassemic proerythroblast membranes remains unknown. These profound membrane alterations would likely contribute to the intramedullary lysis seen in Cooley's anemia.